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    <title>Document</title>
</head>
<body>
    <script>
        new Promise((res, rej) => {
            console.log(111);
            res('成功');
            
        })
        .then(res => {
            console.log(222)
            new Promise((res, rej) => {
                console.log(333);
                res('成功2');
            })
            .then(res => {
                console.log(444);
            })
            .then(res => {
                console.log(555);
            })
        })
        .then(() => {
            console.log(666);
        })  
        //1 2 3  4 6 5
        //1 2 3 4 5 6 
    </script>
</body>
</html>